A Loyola Medicine study suggests it may not be necessary for knee replacement patients to wait up to two weeks after surgery before showering, as many surgeons now require.

The study compared patients who were allowed to shower two days after surgery with patients who had to wait 10 to 14 days. Researchers performed bacterial culture swabs of skin next to incisions, and no differences were found between the early-shower and delayed-shower groups. No patient in either group experienced an infection. As expected, patients overwhelmingly preferred being allowed to shower early.

The study is published in the Journal of Arthroplasty. Corresponding author is Harold Rees MD, an orthopaedic surgeon at Loyola University Medical Center who specializes in knee and hip replacements. Dr. Rees is an assistant professor in the department of orthopaedic surgery and rehabilitation at Loyola University Chicago Stritch School of Medicine.

There have been extensive studies on how to prepare orthopaedic surgical sites to reduce the risk of infections, but relatively little research on post-operative wound care regimens. With little evidence-based guidance, individual surgeons base their showering guidelines on anecdote rather than scientific evidence.

Many orthopaedic surgeons do not allow their patients to get their incisions wet until after the sutures or staples are removed, typically around two weeks after surgery. This is a big inconvenience for knee and hip replacement patients who must find creative ways to bathe the rest of their bodies while keeping their incisions dry, Dr. Rees and colleagues write.

The study included 32 patients who underwent knee replacement surgery to treat bone-on-bone arthritis. All surgeries were performed by Dr. Rees. Sixteen patients were randomly assigned to the early-shower group and 16 were randomly assigned to the delayed-shower group. The early-shower patients were allowed to shower two days after surgery, after their dressings were removed. Patients in the delayed-shower group were not allowed to shower until 10 to 14 days after surgery.

Following surgery, 94 percent of the early-shower group and 81 percent of the delayed-shower group reported that early showering was important to them, and that they would have preferred to do so if given the choice.

The researchers said the study is limited by its small sample size. “What is needed now is a larger-scale study that can evaluate if early versus delayed wound cleaning has any effect on surgical site wound infection risk for total knee arthroplasty [knee replacement surgery],” researchers wrote.